Create a unique ad group with keywords and copy geared toward Mother's Day--you can pause it once the occasion has passed and rerun the campaigns with minor tweaks next year.
Highlight specific benefits like extended or overnight shipping, gift cards and gift-wrapping clearly in either your ad copy or on the landing page--as these details may be exactly what searchers are looking for. And for users wary of giving credit card details over the Net, offer multiple payment options, like Google Checkout or PayPal, to assuage any concerns.